fuel quality measurements at small-scale lbg refuelling stations … · 2017. 1. 4. · westport...

Fuel quality measurements at small-scale LBG refuelling stationsAnders Karlsson, SP LNG Workshop 2016-06-16, NPL, London, UK

LNG / LBG in Sweden

LNG / LBG in Sweden

Since 2010 the station located in Gothenburg, Sweden delivers liquefied

biomethane to heavy and medium duty trucks. But in rare occasions, the tank

may be filled with LNG.

The LNG/LBG is delivered from a biogas plant by a trailer

BOG

CNG

LNG

Gas quality variation

• The truck engines are based on different technologies

• Depending on the technology the engine is more or less sensitive to different

fuel qualities or specific parameters

• The engine technologies have different critical design criteria and can be

optimized for a larger or smaller window.

• Typically, dual fuel technology is more sensitive to varying gas qualities

compared to spark ignited engines in terms of knocking. However, spark ignited

engines are optimized based on specific gas properties.

LNG Blue Corridor

Jönköping is one of the stations of the LNG blue corridor

LNG Blue corridor, gas quality discussion

Aspects to be considered, related to gas quality, which affect the engine and gas

infrastructure:

Hydrogen: Risk of embrittlement for the metallic materials

Water: Risk of corrosion and driveability problems.

Hydrogen sulfide: Corrosive in the presence of water, could affect after-treatment devices,

combustion products could cause problems by sticking to the engine valves.

http://lngbc.eu/

LNG Blue corridor, gas quality discussion

Key parameters discussed regarding LNG and EURO 6 engines are:

Methane Number: The higher MN the better possibility to optimize engine

Wobbe Index: Narrow interval helps to fulfil EURO 6 in terms of specified power and

torque.

Temperature/Pressure: Technology road path indicates need of two pressure intervals:

Spark ignited: minimum ~10 bars HPDI and similar technologies: “As cold as possible”

Siloxanes: Limit needed to secure engine durability (risk of abrasion and increased

probability for knocking)

http://lngbc.eu/

Task 2.4. Ageing effects at LNG/LBG storage and filling stations

Boiling

temperature

(°C)

Nitrogen -195.80

Methane -161.49

Ethane -88.63

Propane -42.07

n-Butane -0.50

i-Butane -11.73

Neo-Pentane 9.50

i-Pentane 27.85

n-Pentane 36.07

Carbon dioxide -78.50

http://www.gastechnology.org/Training/Documents/LNG17-proceedings/Storage-4-Angel_Benito.pdf

Task 2.5. Particulate measurements of LNGStakeholder comments

Westport Innovations Inc. (Westport), engineering the world's most advanced natural gas engines and vehicles, is making progress with its Westport High Pressure Direct Injection (Westport™ HPDI) second generation or "HPDI 2.0" development program. The Westport™ HPDI technology is particularly adapted for heavy duty LNG trucks. In October 2015, Westport announced it has entered into new agreements with Volvo Group governing the development, commercial launch and supply of Westport™ HPDI 2.0 technology in its heavy-duty trucks over the next several years.One specific feature of the HPDI system is its high pressure LNG pump located in the LNG tank, which does have a low tolerance to particles. To achieve customer expectations for product cost and LNG pump maintenance intervals at launch, the LNG needs to be delivered clean. Solid particles would otherwise grind the seals and the coating of the pump, leading gradually to material loss from the seals, resulting in turn in LNG pump performance falling below the required fuel delivery rate. Contaminations have been observed by measuring the rate of seal wear at stations equipped with an appropriate fuel filter compared to stations without a fuel filter, showing that the rate of seal wear significantly increases at the latter ones.Measuring the currently available LNG quality with regards to particles is necessary to evaluate the LNG fuel cleanliness and must be done following the same process at all tested sites in order to provide comparable results. These results are needed to develop future onboard filtration solutions and to define filter maintenance intervals. The LNG sampling equipment and particles measurement process will also be a useful diagnostic tool to resolve operational issues.

LNG / LBG in Sweden: Sampling conditions

Task 2.2. Improved Sampling Techniques

Space a limiting factor




Insulation required to avoid pre-

vaporization




Insulation required to avoid pre-vaporization

Sampler: Mobile

Time for sampling limited -> needs to be quicklystabilized (temperatures/flow)

A heated and insulated coil of 6m ¼″-SS tubing -> high linear velocity

5 measurement ports (temperature)


Effects of heating and

flow rate

Unit With warming Without

warming

With

warming

T1 °C -140 ± 5 -135 ± 5 -100± 5

T2 °C -80 ± 5

T3 °C -20 ± 5

T4 °C 0 ± 5

T5 °C 35 ± 5 -135 ± 5 40 ± 5

Gas flow l/min stable at 60 ± 5

l/min*

Unstable (up to

115 but often

about 60 ± 5

30 ± 5 l/min*

P bar 2 5 1-1.2

Liquid LBG

visible at the

end of the

sampler


Effects of heating and

flow rate 2015-08-21 Theoreticalvalues

Measurements

Vol-% 60 l/min 30 l/min

Methane 98.95 98.95 ± 0.2 99.1

Ethane 0.153 0.145 ± 0.01 0.017 ± 0.01

propane 0.020 0.025 ± 0.01 0.002 ± 0.01

Isobutane 0.003 0.003 <0.001

Butane <0.001 <0.001 <0.001

Oxygen 0.185 0.22 ± 0.05 0.15 ± 0.05

Nitrogen 0.691 0.65 0.75

Carbon dioxide 0.000 <0.1 <0.1

Isopentane 0.000219 0.00035 <0.001

Thank you for your attention!